(78q) When Is a RIK Not a RIK?

Replacements in Kind (RIKs) generally receive less rigorous treatment in the change management process, because they are assumed to present little or no process risk. This paper describes a change to a control valve actuator, classified as a RIK.

During a unit shutdown several weeks prior to the incident, an older model control valve was replaced with a new valve. The old valve had an external transducer, where the new valve's transducer is built into the valve. This change necessitated a 10 foot section of instrument wire be added to the system around the platform to connect the new valve, which resulted in a butt splice in the wire. When the conduit was opened to inspect the butt splice, water was found in the conduit, most likely from the rain that had begun the evening of the incident (the first significant rain since the end of the unit shutdown.) When the water was drained and the splice repaired, the new valve operated properly from the DCS.

This change, which did not involve penetration of the primary process containment boundary, nonetheless led to a significant loss of containment event.

The investigative steps to identify the failure mechanism will be discussed, as well as modifications made to the MOC system to better classify and capture such ?non-change changes.?